Field of Invention
The present invention relates to a gasification furnace and gasification method, and more particularly to a pulverized coal gasification furnace with multi-level feeding of high speed circulating gasification agent and gasification method, which belongs to the field of coal gasification.
Description of Related Arts
Coal gasification technologies are highly efficient and clean coal technologies. The current gasification technologies are categorized into four groups: moving bed gasification, fluidized bed gasification, entrained bed gasification and molten bath gasification. Since entrained bed gasification has the advantages of high gasification level, great production power and high rate of coal conversion, this is the current major development direction in coal gasification technologies. The entrained bed gasification has two major characteristics. First, the operation temperature is high, approximately 1300° C.˜1600° C., the ash formed inside the gasification chamber is in fluid state. The other characteristic is “slag for slag resistance” technology which is used to protect the furnace body and to reduce heat loss. The drawback of existing entrained bed gasifier (see FIG. 18) are as follows: (1) the burner has a short life. The average lifetime of a burner is around 1 year. (2) The inner surface of the gasification furnace is easily damaged. This problem will lead to the frequent stop of operation of gasifier. As gasifiers are the production source for chemical industry, the stop in operation will cause a complete shutdown of the entire production line, and the shutdown of the entire production line will result in a huge economic loss to the company. For example, the economic loss of a one-time shutdown of a gasification production line with a gas production capacity of 80000 Nm3/h is more than 40 million yuan. (3) There is uneven temperature distribution along the height direction and problem of local overheating.